CROSBY, N.D. - Not many years ago, this outpost in extreme northwest North Dakota was considered a sleeper assignment by U.S. Fish and Wildlife Service officials. Ducks in particular -- but also sharp-tailed grouse, golden eagles, bitterns, hawks, falcons and countless other species -- were bountiful, nurtured in part by quality habitat on the region's nearly 100 waterfowl production areas.

Offering still more protection to wildlife were thousands of acres of private wetlands and grasslands under federal conservation easement.

Then advances in drilling technology sparked North Dakota's latest oil boom, wildly altering the region's land and people virtually overnight.

Now semitrailer trucks crisscross the region's two-lane roads 24 hours a day, seven days a week, some carrying oil, others fresh or salt water. Often the big vehicles trail long plumes of dust that one county spent $700,000 in unbudgeted funds last year attempting to control, with little success.

Meanwhile, thousands of workers have migrated to the region seeking high-paying jobs with Exxon-Mobil, ConocoPhillips, Halliburton and other companies, many living either in RVs or the many "man camps" that sprout from farm fields throughout the 14,000-square-mile oil patch.

Feasting, often, on convenience-store favorites Mountain Dew and Hot Stuff pizza, everyone from Bismarck to Bowbells seems on the run, chasing big money. Yet the rush to pump oil from the Bakken Formation encased in shale about 2 miles beneath the Earth's surface seems only just beginning: Almost 7,500 producing oil wells were online in North Dakota in July, a record but a mere fraction of the estimated 50,000 or more that someday might blanket western North Dakota, according to officials.

None of which is good for ducks or other wildlife, including elk, bighorn sheep, mule deer and antelope, in a region whose vitality for millennia has been measured in its unbroken landscape.

"The biggest impact from oil is fragmentation of the countryside," said Lloyd Jones, Fish and Wildlife Service manager at Audubon National Wildlife Refuge near Coleharbor, N.D. "We've had contiguous areas of native prairies and grasslands and wetlands up here forever that have provided extremely valuable and richly diverse habitat.

"When you break that up, which is being done now with the expansion of drilling, you change the picture very dramatically for wildlife. And unfortunately, it's all negative. There's nothing positive about it."

Last year, after considerable delay, and amid widespread speculation that Gov. Jack Dalrymple was withholding it, North Dakota game and fish officials released a thorough study of drilling's possible impacts on a wide range of wildlife. But the state's Legislature hasn't yet followed up with a mitigation plan for resident big game or migratory birds. And a proposed constitutional amendment that would have directed millions in state oil revenue to conservation was derailed this summer when 10 North Dakota State University football players were convicted of election fraud for listing fictitious names on a ballot petition.

For the approximately 8 percent of the prairie pothole region's ducks that nest in the oil patch, the threat is especially untimely.

Already North Dakota and South Dakota are being counted on by wildlife officials to produce ever-greater shares of North America's prairie ducks, because in recent decades Canadian wetlands and other habitat have been drained, burned or plowed.

In the United States, farmers for more than a quarter-century have been paid by the federal Conservation Reserve Program (CRP) to retire marginally tillable land, reduce erosion and increase wildlife habitat. But Canada has had no similar large-scale plan. As a result, much of Canada's prairie duck production has shifted to the Dakotas.

But government budget cuts and record-high commodity prices, together with the advent of genetically modified crops, are prompting many U.S. farmers -- including many in duck-rich North Dakota -- to pull out of CRP and similar programs.

Just this month, North Dakota had a net loss of 642,000 CRP acres that likely will fall to the plow next spring.

'Hard to keep up'

In a nondescript government building just south of Crosby, Fish and Wildlife Service refuge specialist Shea Magstadt spends most of his days thinking, and talking, not about wildlife, which he's trained and paid to do, but about oil and oil drilling.

"I get about 15 e-mails a day I have to respond to that are oil-related," Magstadt said. "That's in addition to the phone calls from oil company employees seeking information about where our conservation easements are, or asking other questions, most of it having to do with well placement."

Located in Divide, Burke and Williams counties, the service's Crosby Wetland Management District, which Magstadt helps oversee, encompasses 17,000 acres of waterfowl production areas (WPAs). Conservation easements on the district total more than 66,000 acres.

Oil companies can't drill on the WPAs. But landowners reserve mineral rights on the easement acres, and wells often rise from them. Additionally, many wetlands outside the WPAs are subject to drilling because North Dakota, unlike Minnesota, has no wetlands protection law.

"An oil 'land man' might call to say his company is thinking about placing a well in the northeast corner of section 7, for example," Magstadt said. "So I might look at multiple images of the site trying to determine historical wetland records, then advise the oil company where the [well] pad should go to cause the fewest problems.

"In the end I might say, 'Can we turn the pad this way, or cut a corner off it?' A lot of these companies are willing to work with us. They want to do the best job they can. We've published best-management guidelines for them to use. But all of this is going at an incredible pace. We're understaffed. It's hard to keep up."

Months can pass between the time construction of a drilling pad begins and a hole is bored about 2 miles beneath the surface, then extended another 2 miles or so horizontally.

Only then is the well "fracked," meaning shale containing the oil is cracked under extreme pressure in multiple places using a mixture of water, chemicals and sand. The oil subsequently seeps from the shale and is pumped to the surface, where it's either trucked or carried by pipeline to depots.

Because the fracking occurs so far beneath the surface, it's believed not to be a risk to drinking water in North Dakota, as some say the process has been in other states.

But disturbance caused by the estimated 2,000 to 2,500 trucks needed to build a pad and well and haul the vast amounts of water needed for drilling (some of it is pumped directly from wetlands) is what concerns wildlife managers.

"If birds won't nest within a couple hundred yards of a wind turbine -- and research says they won't -- they sure as hell aren't going to nest near an oil well, especially while it's being built," said Mike McEnroe, a retired Fish and Wildlife Service wildlife biologist who represents natural resource professionals at the North Dakota capitol.

Oil spills, McEnroe said -- while perhaps uncommon -- are also a concern, as is disposal of salt water and the mix of sludge that accompanies well drilling.

'Really important'

Kory Richardson manages the 27,000-acre Lostwood National Wildlife Refuge near Kenmere, N.D., which lies not only in the state's oil patch but within the Missouri Coteau, a glacial moraine that extends across North Dakota, northwest to southeast.

Designated a "globally important bird area" by the American Bird Conservancy, the refuge is home not only to ducks but to threatened species such as the piping plover.

Until recently, Richardson managed Ilo National Wildlife Refuge, also in the North Dakota oil patch, which is entirely surrounded by wells.

"If you communicate with the oil companies early in the process, they'll work with you on well placement," Richardson said. "But outside of our [federal] refuges and waterfowl production areas, there's no protection for other lands I'm aware of. This is especially true for small, temporary wetlands that might be filled only in spring or during wet years. Those are really important to birds, ducks in particular."

Increased funding, much of it from the sale of federal duck stamps, made available recently for additional grassland and wetland easements in the Dakotas will counter some downsides associated with drilling.

"But that will only conserve wetlands and grasslands that already exist, not replace what's being lost," McEnroe said.

That's because in the Bakken, federal wildlife officials say, oil money trumps wildlife protection 24 hours a day, seven days a week.

Dennis Anderson • danderson@startribune.com Twitter: @stribdennis